Mounting of electrode structures in envelopes



F 1951 L. J. c. BAYFORD ET AL 2,542,108

MOUNTING 0F ELECTRODE STRUCTURES IN ENVELOPES Filed Oct. 20, 1948 9 [OI/2208 l4 INVENTORS LESLIE JOHN CHARLES BAYFORD THOMAS HENRY FULCHER Patented Feb. 20, 1951 MOUNTING OF ELECTRODE STRUCTURES .v IN ENVELOPES Leslie John Charles Bayford, Hayes, and Thomas Henry Fulcher, Hillington, England, assignors to Electric & Musical Industries Limited, Hayes, England, a company of Great Britain Application October 20, 1948, Serial No. 55,504 In Great Britain October 25, 1947 6 Claims.

This invention relates to the mounting of electrode structures in envelopes, such as the mounting of an electron gun structure in the envelope of a cathode ray tube.

Usually electrode structures which are to be mounted in envelopes are made of a unitary construction, that is to say, one or more electrodes are assembled together to form a structure which can be inserted as a whole in the envelope or neck portion of a cathode ray tube. It is necessary to" maintain said structure in a predetermined position with respect to the axis of the envelope and providing the envelopeismade to a reasonable degree of accuracy, the electrode structure can be located in a predetermined position with respect to the axis of the envelope by causing the electrode structure to engage the internal wall-of the envelope. 7

The object of the present invention is to provide an electrode structure having improved means for causing engagement of said structure with the internal wall of the envelope.

According to the present invention there is provided an electrical device having a unitary electrode structure mounted in the envelope of said device, said structure having means at at least three points which surround the axis of said structure, said means at two of said points being relatively rigid, whilst said means at another of said points is resilient, said means engaging the wall of the envelope so as to maintain the said structure in position.

The invention is of particular use in the mount- As shown in Figure 1, the reference numeral l indicates the envelope of a cathode ray tube such ner, The gun 3, as shown in Figure l, is of the tetrode type and comprises a cathode 6 enclosed within a modulating electrode, a first anode l and a second anode 8, these electrodes being of tubulari'orm and being assembled into a unitary structure by connecting said electrodes to circular metal discs 9, Ill, I I, I2 and 13 which are in i turn assembled on three insulating rods l4, l5

and It which are disposed equi-distantly about the axis of the electron gun. The cathode and modulating electrode 6 are mounted on the two discs 9 and iii, the first anode I on the disc II and the second anode 8 on the two discs 12 and l3. The rods I l, l 5'and [6 are preferably made of ceramic material and the discs 9, I0, I i2 and I3 are clamped to the rods through the medium of metal sleeves ll, welded to the discs, the sleeves being clamped around said insulating rods.

ing of electrode structures in the neck portions of cathode ray tubes, although it will be appreciated that the invention is equally applicable for use in connection with other electrical devices where electrode structures are required to be maintained in position in envelopes.

In order that the said invention may be clearly understood and readily carried into efiect, the same will now be more fully described with reference to the accompanying drawings, in which:

Figure 1 illustrates the invention as applied to the mounting of an electron gun in the envelope of a cathode ray tube,

Figure 2 is an elevation of the relatively rigid means provided on the electron gun,

Figure 3 is a cross-sectional View of Figure 2 taken along the line 3-3 of Figure 2,

Figure 4 is a cross-sectional view of the resilient means employed in the arrangement shown in Figure 1, and

Figures 5 and 6 illustrate electron guns having modified formations of supporting means.

" gu'n 3.

In order to maintain the gun 3 in a predeter- ,mined position with respect to the axis of the neck portion 2 rigid means are provided for engaging the internal wall of the neck portion 2 at two points and resilient means are provided for' engaging the wall of the envelope at another point, said points surrounding the axis of the The rigid. means comprise rigid metal members I8 and 19 of substantially circular form,

, as shown in Figure 2, welded to certain of said discs, a portion of the periphery of each member I 8 and I9 projecting beyond the peripheries of the disc so as to be capable of engaging the in ternal wall of the neck portion 2. Two metal members l8 and 19 are provided on the disc i0 and a further two members 18 and I9 are provided on the disc l3, said members It and 19 on the discs Ill and I3 being aligned with respect to I one another. Said resilient means comprises a spring finger 20, (Figure 4), which is welded to the disc l2, said spring finger, as shown comprising a strip of flat metal the end of which is bent outwardly and extends towards the glass disc 4. The members I8 and I9 and the spring finger 20 are equi-distantly disposed about the axis of the structure 3. The spring finger 20 is disposed axially of the length of the structure 3 in a position substantially midway between the planes GQntaining the pairs or metal members I! 3 and Hi. It will be observed from Figure 2 that the resilient spring finger 20 is disposed in a plane through the axis of the structure and between the rigid members 18 and I9. In assembling the gun 3 in the neck 2 of the cathode ray tube, the gun 3 is first connected to the glass disc 4 and is then inserted into the neck portion 2, the spring finger serving to urge the metal members l8 and [9 into engagement with the wall of the neck portion 2 and providing the neck portion is reasonably accurately made, the gun 3 will be disposed in a predetermined position with respect to the axis of the envelope. After insertion the glass disc 4 is sealed to the end of the neck portion 2, as usual. The arrangement shown in Figure 1 of the drawings serves to maintain the axis of the gun 3 in alignment with the axis of the neck portion 2 even though only one spring finger 20 is employed. If desired, however, the discs '12 and 13 which carry the pairs of metal members 18 and I9 may each be provided with a spring finger 20, as shown in Figure 5. In some cases the invention can be applied for the purpose of centralising the gun 3 in the neck portion 2, alignment of the axis of the gun with the axis of the neck portion being made during sealing of the disc 5 to the neck portion 2. In these cases the gun shown in Figure 6 of the drawings can be employed this gun being of the triode type which comprises a cathode 6 enclosing a modulating electrode and an anode I, the cathode being mounted on two metal discs 9 and lil and the anode '1 on a single metal disc 12. The anode 1 may if desired be in the form of a conducting coating on the wall of the envelope in which case the gun will merely comprise the cathode and modulating electrode. In this arrangement the disc I2 is provided with rigid metal members l8 and 19, only one of which is shown in Figure 6, said disc also being provided with a spring finger 20. With this arrangement, when the electrode structure is inserted in the envelope the members 18 and I9 and the spring finger 20 serve to centralise the gun in the neck portion 2, alignment of the axis of the gun with the axis of the neck portion being obtained by adjustment of the disc 4 relatively to the neck portion.

Although the invention has been described as applied particularly to the mounting of an electron gun of a cathode ray tube, it will be understood that the invention can be employed in other devices, such as devices of the velocitymodulation type and to electrode structures other than those embodying a cathode.

What we claim is:

1. An electrical device including an envelope and a unitary electrode structure mounted therein, said structure having means at at least three points surrounding the axis of said structure and engaging the wall of the envelope to maintain said structure in position, said means at at least two of said points being substantially rigid whilst said means at another of said points is resilient, said resilient means lying in a plane through said axis and between said other two points.

2. An electrical device according to claim 1, wherein said substantially rigid means are disposed in at least two transverse planes spaced along the axis of said structure to align the structure with the axis of said envelope.

3. An electrical device according to claim 1, wherein said resilient means is disposed between said planes.

4. An electrical device according to claim 1, including electrodes and supports therefor, said substantially rigid means comprising elements projecting beyond the periphery of said electrode supports.

5, An electrical device including an envelope and a unitary electrode structure mounted therein, said electrode structure having a mounting comprising means engaging said envelope at three points spaced around the axis of said structure, said means at two of said points being rigid, and said means at the other of said points being resilient, said resilient means lying in a plane passing through said axis and between said other two points.

6. An electrical device including an envelope and a unitary electrode structure mounted therein, said electrode structure comprising a plurality of discs carrying the electrodes of said structure, rods extending longitudinally of said structure and passing through said discs, one of said discs having two rigid members projecting from the periphery thereof and one of said discs having a resilient finger projecting therefrom, said rigid members and said finger being substantially equidistantly spaced about the longitudinal axis of said structure and engaging the inner surface of said envelope, said resilient finger lying in a plane passing through said axis and between said rigid members.

LESLIE JOHN CHARLES BAYFORD. THOMAS HENRY FULCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,362,908 Liebmann Nov. 14, 1944 2,452,620 Weimer Nov. 2, 1948 FOREIGN PATENTS Number Country Date 519,111 Great Britain Mar. 18, 1940 

